#pragma comment(linker, "/STACK:10000000")
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <set>
#include <map>
#include <cstdio>
#include <cassert>
#include <string>
#include <cstring>
#define ldb long double
#define LL long long
#define fi first
#define se second
#define fill(a, c) memset(a, c, sizeof(a))
#define sqr(a) ((a) * (a))
#define nextLine() {int c = 0; while((c = getchar()) != 10 && c != EOF);}
#define getBit(mask, k) (((mask) / pw[k]) % pw[1])
#define setBit(mask, k, l) (((mask) / pw[k + 1] * pw[1] + (l)) * pw[k] + ((mask) % pw[k]))
#define debug(a) cerr << #a << " = " << a << " ";
#define debugl(a) cerr << #a << " = " << a << "\n";
const ldb LDINF = 9128739847123.00;
const ldb eps = 1e-9;
const int INF = 1 << 30;
const ldb pi = fabsl(atan2(0.0, -1.0));
using namespace std;

int a, n, m, b;
void Load()
{
	cin >> n >> m >> a >> b;
}

void Solve()
{
	a--;
	b--;
	if ((a % m) == 0 && (b % m) == m - 1)
	{
		cout << 1;
		return;
	}
	if (a / m == b / m)
	{
		cout << 1;
		return;
	}
	if ((a % m) == 0 || (b % m) == m - 1)
	{
		if (b == n - 1 && (a % m) == 0)
			cout << 1;
		else cout << 2;
		return;
	}
	if (a / m + 1 == b / m)
	{
		cout << 2;
		return;
	}
	if ((a % m) == (b % m) + 1)
	{
		cout << 2;
		return;
	}
	if (b == n - 1)
		cout << 2;
	else
	cout << 3;
}

#define file "a"
int main()
{
	#ifndef ONLINE_JUDGE
		freopen(file".in", "rt", stdin);
		freopen(file".out", "wt", stdout);
	#endif
	Load();
	Solve();
	return 0;
}
